1. Field of the Invention
The present invention relates to an electronic component and an electronic device, and more particularly, to an electrochemical cell such as an electric double-layer capacitor.
2. Description of the Related Art
The electric double-layer capacitor is a device which is charged through polarization of ions in an electrolyte and discharged, thereby supplying electric power.
The electric double-layer capacitor is characterized by this charging/discharging function, and hence is used, for example, in backup power sources for a clock function and a semiconductor memory for electronic devices, or used in standby power sources for electronic devices such as microcomputers and IC memories.
In particular, the electric double-layer capacitor capable of surface mounting can be downsized and reduced in thickness, and hence is suitable for thin mobile terminals.
In order to meet such demands for downsizing and reduction in thickness, the following Japanese Patent Application Laid-open No. 2001-216952 proposes an electric double-layer capacitor in which a polarizable electrode and an electrolyte are accommodated in a container including a recessed portion and an opening portion is sealed with a sealing plate.
FIG. 24 is a cross-sectional view of a conventional electric double-layer capacitor 100.
On a bottom surface of a recessed container 102, which has formed therein a recessed portion 110 having inner walls perpendicular to the bottom surface and is made of a ceramics, a metallic layer 126 is provided. An electrode 121 (positive electrode) is bonded onto an upper surface of the metallic layer 126.
The metallic layer 126 passes through the recessed container 102 to be electrically connected to an external electrode 127 on a rear surface of the recessed container 102. In this manner, the electrode 121 is electrically connected to the external electrode 127 via the metallic layer 126.
A sealing plate 103, made of metal, is bonded to an upper end portion of the recessed container 102 via a bonding metallic layer 106, thereby sealing the recessed portion 110. Note that, a metallic layer 104 is formed on a lower surface of the sealing plate 103, and the metallic layer 104 is bonded onto the bonding metallic layer 106.
On a side surface of the recessed container 102, there is formed a metallic layer 116 that connects the bonding metallic layer 106 to an external electrode 117 provided on the bottom surface of the recessed container 102.
An electrode 111 (negative electrode) is bonded onto the metallic layer 104 provided on the lower surface of the sealing plate 103, and is electrically connected to the external electrode 117 via the metallic layer 104, the bonding metallic layer 106, and the metallic layer 116.
Between the electrode 111 and the electrode 121, there is provided a separator 107 for preventing the electrodes from short-circuiting, and further, an electrolyte is sealingly filled in the recessed portion 110.
The electric double-layer capacitor 100 thus structured stores charges when a voltage is applied to the external electrodes 117 and 127, and releases the stored charges to supply power for maintaining a clock function, to supply power to a memory, and to supply power for other purposes.
However, the electric double-layer capacitor 100 is manufactured in a manner that the electrode 111 is strongly adhered by a conductive adhesive onto the sealing plate 103 with its lower surface facing upward, and thereafter the sealing plate 103 is turned upside down to seal the recessed container 102. This process complicates the manufacturing steps and is responsible for lowered yields.